The Ottawa Senators promised they were going into rebuild mode earlier this week. They weren't kidding.

Ending months of speculation and creating yet another juicy headline, the Senators traded their franchise player — captain Erik Karlsson —to the San Jose Sharks on Thursday.

In the end, the defenceman and the Senators did not see eye to eye — with the deal being done on the eve of the first on-ice session at training camp.

"I don't think I could have ever prepared for this, that's why I don't have anything written and I still haven't wrapped my mind around what is going on," said an emotional Karlsson. "As you said, there's been a lot of noise for almost a year now, but I never in my wildest imagination thought that I was going to leave this place."

Ottawa receives San Jose's first-round choice in either 2019 or 2020 (not lottery protected). If the Sharks miss the playoffs in 2018-19, it will be a 2019 selection, otherwise it will be in 2020. Ottawa gets a second-round choice in the 2019 draft from San Jose (which will be the higher of the two picks the Sharks currently own — the Florida Panthers' and their own).

The deal is sure to be a defining moment for a team that has had all kinds of problems on and off the ice in recent months.

The Senators took the unusual step of releasing a video late Monday night with defenceman Mark Borowiecki interviewing owner Eugene Melnyk, who made it clear the team was ready to rebuild. Many interpreted it as a sign that Karlsson's days in Ottawa were numbered.

"This is the right moment for us to rebuild our team," said Senators general manager Pierre Dorion. "Shape our future with all these core pieces while adding a faster, younger and more competitive team on the ice. This trade represents the best opportunity for the Ottawa Senators to rebuild towards a consistent excellence that we are striving for."

Dorion admitted the decision to rebuild was made in February, yet during town hall meetings with fans in April said, "at the end of the day it will be (Karlsson's) choice. If we offer him a fair contract and he doesn't want to sign here, then we will have to look at other options. The ball will be in his court.”

Karlsson, whose contract expires at the end of this season, doesn't quite see it that way.

"I think they made it very clear in what direction they were going with and unfortunately I wasn't part of that and I respect that it's their decision," he said. "I was not part of that plan and that's why we're standing here today. From my point of view, that's sad. I never wanted to leave this place, but at the same time I respect their decision."

The Senators, who did offer Karlsson an extension over the summer, believed this was the best option.

"You get to a certain point and it's probably best for all parties to move on," said Dorion. "For the benefit of the organization, for the benefit of the rebuild, for the succession of the rebuild, I think today we made the proper decision."

Selling that to the fans may be difficult, though. There were thousands of empty seats for some games last season, and the organization figures to face a similar challenge in 2018-19.

Karlsson is a two-time Norris Trophy winner and led or tied the Senators in scoring the past five years.